Organic light emitting display

ABSTRACT

A method of making a display device includes forming first electrodes of organic light emitting diodes in respective pixel areas on a substrate, forming a first common layer on the first electrodes in the pixel areas, forming emission layers in the pixel areas on the first common layer, forming a second electrode of the organic light emitting diodes on the emission layer, and applying physical pressure to divide the first common layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application based on pending application Ser. No.14/321,033, filed Jul. 1, 2014, the entire contents of which is herebyincorporated by reference.

Korean Patent Application No. 10-2013-0077107, filed on Jul. 2, 2013,and entitled, “Organic Light Emitting Display and Fabricating MethodThereof,” is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

One or more embodiments described herein relates to a display device.

2. Description of the Related Art

The performance of displays must increase as information technologyevolves. Flat panel displays have been developed in pursuit of thisgoal. One type of flat panel display, known as an organic light emittingdiode (OLED) display, has pixels which output light based on arecombination of electrons and holes in corresponding active layers.Displays of this type have demonstrated relatively fast response speed,low-voltage driving and power consumption, and excellent viewing angle.

SUMMARY

In accordance with one or more embodiments, a method of making a displaydevice includes forming first electrodes of organic light emittingdiodes (OLEDs) in respective pixel areas on a substrate, forming a firstcommon layer on the first electrodes in the pixel areas, formingemission layers in the pixel areas on the first common layer, forming asecond electrode of the OLEDs on the emission layer, and applyingphysical pressure to divide the first common layer. Applying thephysical pressure may include applying a force to the first common layerin a different direction of a plane including the substrate.

Applying the physical pressure may include placing a panel on asubstrate support having a plurality of grooves, the panel including thefirst electrodes, the first common layer, the emission layers, and thesecond electrode, and moving at least one of the panel or the substratesupport in a second direction intersecting a first direction, whileapplying a force in the first direction to divide the first commonlayer. The substrate support may include first and second regions, eachhaving grooves at a predetermined interval, the grooves in adjacentregions alternately positioned to cross each other. The first directionmay be perpendicular to the second direction.

The method may include moving the panel onto the second region on thesubstrate support when at least one region of the panel is positioned inthe first region on the substrate support, wherein moving the panelincludes applying the force to the panel in the first direction. Each ofthe first and second regions of the substrate support may include aplurality of grooves having substantially a same interval and width.

Applying the physical pressure may include applying a force to a panelin a first direction while rotating at least one roller in a seconddirection crossing the first direction, the at least one rollerincluding a plurality of grooves and the panel including the firstelectrodes, the first common layer, the emission layers, and the secondelectrode.

Applying the physical pressure may include rotating a plurality ofrollers on the first common layer, each of the rollers having grooves ata predetermined interval and the rollers are rotated so that the groovesof the rollers are alternately positioned.

Applying the physical pressure may include rotating a plurality ofrollers on the first common layer, each of the rollers having aplurality of diagonal grooves.

A number k OLEDs may share the first common layer, where k≧2, and one ormore pixels having a number smaller than the k pixels may share thedivided first common layer. Pixels in a horizontal or vertical line mayshare the first common layer, and applying the physical pressure mayinclude dividing the first common layer into at least two first commonlayers. At least two first common layers may be divided relative to thehorizontal and vertical pixel lines.

Forming a second common layer on the emission layer may allow aplurality of pixels to share the second common layer, and the secondcoming layer may be formed between forming the emission layers andforming of the second electrode. The second common layer may besimultaneously divided with the first common layer.

The first electrodes and emission layers may be patterned forcorresponding pixels, and the second electrode may be entirely formed ona pixel unit so that all the pixels share the second electrode.

In accordance with another embodiment, an organic light emitting displayincludes a plurality of pixels, each of the pixels including at leastone organic light emitting diode (OLED) which includes: a firstelectrode and an emission layer in a respective pixel area, a firstcommon layer between the first electrode and emission layer, and asecond electrode on the emission layer, a plurality of pixels sharingthe first common layer, wherein the first common layer is divided withrespect to a horizontal or vertical pixel line.

The first common layer may be disposed to be divided with respect tohorizontal and vertical pixel lines. The OLED may include a secondcommon layer between the emission layer and second electrode, and aplurality of pixels may share the second common layer. The second commonlayer may be divided with respect to a horizontal or vertical pixelline. The first electrode and emission layer may be patterned for acorresponding one of the pixels, and two or more of the pixels may sharethe second electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates an embodiment of an organic light emitting display;

FIG. 2 illustrates an embodiment of a pixel in the display;

FIG. 3 illustrates a sectional view of the pixel;

FIGS. 4A and 4B illustrate an embodiment of a method for cutting offleakage current in the pixel;

FIG. 5 illustrates divided common layers of an organic light emittingdisplay;

FIG. 6 illustrates an embodiment of a method for dividing a commonlayer;

FIG. 7 illustrates another embodiment of a method for dividing a commonlayer; and

FIG. 8 illustrates another embodiment of a method for dividing a commonlayer.

DETAILED DESCRIPTION

Example embodiments are described more fully hereinafter with referenceto the accompanying drawings; however, they may be embodied in differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully conveyexemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

FIG. 1 illustrates an embodiment of an organic light emitting display.FIG. 2 illustrates an embodiment of a pixel in FIG. 1. Referring to FIG.1, the organic light emitting display includes a pixel unit 20, a scandriver 30, an emission control driver 40, a data driver 50, and a timingcontroller 60.

The pixel unit 20 includes a plurality of pixels 10, each including atleast one organic light emitting diode. The pixels 10 may be arranged,for example, in a matrix form at intersection portions of scan lines S1to Sn and data lines D1 to Dm.

As shown in FIG. 2, pixels 10 include a first color pixel 10R, a secondcolor pixel 10G, and a third color pixel 10B. The first color pixel 10Rincludes a first color OLEDr emitting light of a first color (e.g.,red). The second color pixel 10G includes an OLEDg emitting light of asecond color (e.g., green). The third color pixel 10B includes an OLEDbemitting light of a third color (e.g., blue). Adjacent first to thirdcolor pixels 10R, 10G, and 10B may be considered to form a pixel unitexpressing various colors.

Each pixel 10 may also include a pixel circuit 12 to supply drivingcurrent to the OLED. An example of the configuration and operation ofeach pixel 10 will be described with reference to FIG. 2.

Specifically, each pixel 10 includes a pixel circuit 12 coupled to theOLED. The pixels 10 may be classified into first to third color pixels10R, 10G, and 10B according to the color of light emitted from theirOLEDs.

A first electrode (e.g., an anode electrode) of the OLED is coupled to afirst pixel power source ELVDD via the pixel circuit 12. A secondelectrode (e.g., a cathode electrode) of the OLED is coupled to a secondpixel power source ELVSS. The OLED emits light with luminancecorresponding to driving current from the pixel circuit 12.

Each pixel circuit 12 may include first to third transistors M1, M2, andM3, and a storage capacitor Cst. In other embodiments, the pixels 10 orpixel circuit 12 may have a different structure.

A first electrode of the first transistor M1 is coupled to a data lineD. A second electrode of the first transistor M1 is coupled to a firstnode N1. The first and second electrodes of the first transistor M1 aredifferent electrodes. For example, when the first electrode is a sourceelectrode, the second electrode is a drain electrode, or vice versa. Agate electrode of the first transistor M1 is coupled to a scan line Sn.

The first transistor M1 is turned on when a scan signal having apredetermined voltage (e.g., a low voltage) is supplied from the scanline, to thereby allow the data line D and first node N1 to be coupledto each other. A data signal of a corresponding pixel 10 is supplied tothe data line D. Accordingly, the data signal is supplied to first nodeN1. The charge corresponding to the data signal supplied to the firstnode N1 is stored in the storage capacitor Cst.

A first electrode of the second transistor M2 is coupled to the firstpixel power source ELVDD. A second electrode of the second transistor M2is coupled to the first electrode of the OLED via the third transistorM3. A gate electrode of the second transistor M2 is coupled to the firstnode N1. The second transistor M2 controls the amount of driving currentsupplied to the OLED, based on the voltage at first node N1.

A first electrode of the third transistor M3 is coupled to the secondelectrode of the second transistor M2. A second electrode of the thirdtransistor M3 is coupled to the first electrode of the OLED. A gateelectrode of the third transistor M3 is coupled to an emission controlline En. The third transistor M3 is turned off during a non-emissionperiod in which an emission control signal having a predeterminedvoltage (e.g., a high voltage) is supplied from the emission controlline En. When the third transistor M3 is turned off, the driving currentis cut off so that it does not flow through the OLED.

The third transistor M3 is turned on during an emission period, e.g.,during which supply of the emission control signal is stopped. Theemission period may correspond, for example, to a period in which thevoltage of the emission control signal is set to a low voltage. Duringthe emission period, driving current is supplied from the secondtransistor M2 to the OLED.

One electrode of the storage capacitor Cst is coupled to the first pixelpower source ELVDD. The other electrode of the storage capacitor Cst iscoupled to the first node N1. The storage capacitor Cst charges to avoltage corresponding to the data signal supplied to the first node N1,and stores this voltage, for example, until a data signal of the nextframe is supplied.

The pixel 10 may have a relatively simple structure. For example, pixel10 may include first transistor M1 for supplying a data signal, storagecapacitor Cst for storing the data signal, second transistor M2 forsupplying driving current to the OLED, and third transistor M3 forcontrolling the emission period of the pixel 10, as illustrated in FIG.2. The pixel 10 may have a different structure in other embodiments. Forexample, pixel circuit 12 may include other circuit devices such as atransistor device for compensating for the threshold voltage of thesecond transistor M2 and/or a transistor device for initializing thefirst node N1.

The pixel 10 is selected by the scan signal from the scan line Sn duringa scan period of a corresponding horizontal line. When the scan signalis received, a data signal is transferred from the data line D coupledthereto. In this case, the emission period of the pixel 10 is controlledbased on the emission control signal from the emission control line En.

When driving current corresponding to the data signal is supplied to theOLED, pixel 10 emits light with a luminance corresponding to the drivingcurrent. However, when a black gray scale value is to be displayed inthe pixel in a corresponding period, the data signal may cut off currentto the OLED. Accordingly, the OLED does not emit light to therebydisplay the black gray scale value.

Referring again to FIG. 1, the scan driver 30 selects a pixel line(horizontal pixel line) to receive data signals for each horizontalperiod in one frame, while supplying a scan signal to scan lines S1 toSn. For example, the scan driver 30 may progressively select scan linesS1 to Sn and supply the progressively shifted scan signals to the scanlines S1 to Sn.

The emission control driver 40 controls the emission of pixels 10 on atleast one pixel line, while supplying emission control signals toemission control lines E1 to En. For example, the emission controldriver 40 cuts off driving current flowing through OLED positioned on acorresponding pixel line during a predetermined non-emission period,including a data writing period, of each pixel line. The emissioncontrol driver 40 supplies, to emission control lines E, emissioncontrol signals which enable driving current to be supplied to the OLEDduring an emission period of each pixel line.

The data driver 50 generates data signals based on data supplied fromthe timing controller 60, and supplies the generated data signals topixels 10 through the data lines D1 to Dm.

The timing controller 60 controls the scan driver 30, emission controldriver 40, and data driver 50 based on one or more control signals thatmay be externally supplied.

In the organic light emitting display configured as described above,when scan signals are supplied from scan driver 30 through scan lines S1to Sn, pixels 10 receive the data signals from the data driver 50through corresponding ones of the data lines D1 to Dm. The pixels 10also receive emission control signals from the emission control driver40 through corresponding ones of the emission control lines E1 to En.

Then, driving current with an amplitude corresponding to the datasignals flow through the OLEDs of respective ones of the pixels duringemission periods corresponding to emission control signals, so thatpixels 10 emit light with gray scale values corresponding to the datasignals.

When a black gray scale is to be displayed in a predetermined pixel 10,the data signal is supplied to cut off the driving current flowingthrough the a corresponding OLED during a corresponding period.Accordingly, the OLED does not emit light and thereby implements theblack gray scale value.

However, a path along which leakage current can flow between pixels 10may be formed according to the structure of the pixels 10. For example,the OLED in each pixel 10 may include a common layer shared by aplurality of pixels 10, in addition to a first electrode and an emissionlayer, patterned for each pixel.

In this case, even the pixel 10 receiving a data signal corresponding toa black gray scale value may emit some amount of light. This is becauseleakage current flows through the common layer due to parasiticresistance in the common layer. Therefore, the OLED of a pixel 10intended to implement a black gray scale value is weakly turned on. Inthis case, pixel 10 does not completely express the black gray scalevalue. Therefore, deterioration of image quality may result. This willbe described in detail with reference to FIGS. 3 to 4B.

FIG. 3 illustrates a main-portion sectional view of the pixel in FIG. 2.For illustrative purposes, only the OLED of each pixel 10R, 10G or 10Bin FIG. 2 and a transistor T4 coupled to the OLED will be shown in FIG.3.

Referring to FIG. 3, an OLED including an emission layer 233 of acorresponding color and a transistor Tr (e.g., the third transistor M3of FIG. 2) coupled to the OLED are formed in the region of each pixel10R, 10G, and 10B. Transistor Tr is formed on a substrate 200. Aplanarization layer 210 is formed on the transistor Tr. Here, thesubstrate 200 is formed of glass, plastic, silicon, synthetic resin orthe like.

The planarization layer 210 may be formed of an insulative material suchas a nitride or oxide layer. A via hole 212, through which transistor Trand the OLED are electrically coupled to each other, is formed in theplanarization layer 210.

The OLED coupled to transistor Tr through the via hole 212 is formed onthe planarization layer 210. More specifically, the OLED includes afirst electrode 231, a first common layer 232, an emission layer 233, asecond common layer 234, and a second electrode 235 sequentially formedon the planarization layer 210. The first and second common layers 232and 234 may be selectively provided. In this embodiment, the OLEDincludes at least one first common layer 232 and/or at least on secondcommon layer 234.

The first electrode 231 of the OLED may be patterned for each pixel 10R,10G, and 10B. A pixel defining layer 220 is formed between adjacentpixels 10R, 10G, and 10B, so that the region of each pixel 10R, 10G, or10B can be defined. The pixel defining layer 220 may be made of, forexample, of one or more of an acrylic organic compound or an insulativematerial such as polyamide or polyimide.

The first common layer 232 is formed on the first electrode 231 of theOLED and pixel defining layer 220. The first common layer 232 mayinclude a hole injection layer and/or a hole transport layer. The firstcommon layer 232 may be formed so that the plurality of pixels 10R, 10G,and 10B share the first common layer 232 for the purpose of conveniencein the fabricating process of the organic light emitting display.

For example, the first common layer 232 may be formed in a stripe shapeso that at least pixels for each horizontal or vertical pixel line sharea single first common layer 232. Alternatively, the first common layer232 may be entirely formed on the pixel unit, so that all pixels 10R,10G, and 10B in the pixel unit share a single first common layer 232.

In one embodiment, the first common layer 232 may be commonly formed onthe first electrodes of the pixels 10R, 10G, and 10B, which share firstcommon layer 232 and pixel defining layer 220. The first common layers232 between adjacent pixels 10R, 10G, and 10B may be integrally coupledon the pixel defining layer 220.

The emission layer 233 is formed on the first common layer 232. Theemission layer 233 may be patterned for each pixel 10R, 10G, or 10B tooverlap first electrode 231. The second common layer 234 is formed onthe emission layer 233. The second common layer 234 may include anelectron transport layer and/or an electron injection layer.

Like the first common layer 232, the second common layer 234 may beformed so that a plurality of pixels 10R, 10G, and 10B share secondcommon layer 234. In one embodiment, a plurality of second common layers234 may be patterned in a stripe shape on the pixel unit. Alternatively,a single second common layer 234 may be entirely formed on the pixelunit.

That is, second common layer 234 may be formed to overlap at leastelectrode 231 and emission layer 233. In this case, the second commonlayer 234 may extend to the region of the pixel defining layer 220, sothat the second common layers 234 between adjacent pixels 10R, 10G, and10B can be integrally coupled on the pixel defining layer 220.

The second electrode 235 of the OLED may be formed on the second commonlayer 234. For example, the second electrode 235 may be entirely formedon the pixel unit, but this is not necessary. The second electrode 235may be patterned to have a variety of shapes.

As described above, an OLED is formed in the area of each of pixels 10R,10G, or 10B on the substrate 200. The first electrode 231 the emissionlayer 233 of the OLED is may be patterned in the area of each pixel 10R,10G, or 10B, and the second electrode 235 of the OLED, for example, maybe entirely formed on the pixel unit, so that all the pixels share thesecond electrode 235.

In one embodiment, the OLED in each pixel 10R, 10G, or 10B may includeat least one of a first common layer 232 formed between the firstelectrode 231 and emission layer 233, or a second common layer 234formed between the emission layer 233 and second electrode 235. Thefirst common layer 232 and/or the second common layer 234 may be formedso that a plurality of pixels 10R, 10G, and 10B share the first commonlayer 232 and/or the second common layer 234.

One embodiment of a method of fabricating an organic light emittingdisplay including pixels having OLEDs will now be described. In thisembodiment, the method includes forming a first electrode 231 in an areaof each pixel 10R, 10G, and 10B. A first common layer 232 is formed onthe first electrodes 231 of the OLED, so that a plurality of pixels 10R,10G, and 10B share the first common layer 232. An emission layer 233 isformed in the area of each pixel 10R, 10G, and 10B on the first commonlayer 232. A second electrode 235 of the OLED is formed on the emissionlayer 233.

The method may further include forming a pixel defining layer 220 todefine the areas of pixels 10R, 10G, and 10B. The pixel defining layer220 may be formed between formation of the first electrode 231 of theOLED and formation of the first common layer 232.

The first common layer 232 may be formed on the first electrodes 231 ofthe OLED, so that k pixels (k is a natural number of 2 or more) share asingle common layer 232. For example, in forming first common layer 232,the first common layer 232 may be formed on the first electrodes of theOLEDs, so that pixels 10R, 10G, and 10B on one or more horizontal pixellines and/or one or more vertical pixel lines share a single firstcommon layer 232. The first common layer 232 may be patterned in astripe shape on the pixel unit, or may be entirely formed on the pixelunit.

Previously, the second common layer 234 was indicated to be selectivelyprovided with first common layer 232. In other embodiments, the firstcommon layer 232 may be omitted and only the second common layer 234 maybe formed.

When the first common layer 232 and/or second common layer 234 are/isformed so that a plurality of pixels 10R, 10G and 10B share the firstcommon layer 232 and/or the second common layer 234, the patterningprocess may be simplified, thereby improving efficiency of thefabricating process of the organic light emitting display.

However, in a case where leakage current flows via the first commonlayer 232 and/or the second common layer 234 due to parasitic resistancein the first common layer 232 and/or the second common layer 234, asmall amount of light may be generated in one or more of pixels 10R,10G, or 10B which are intended to implement black gray scale value.Particularly, the second electrode 235 of the OLED is coupled to thesecond pixel power source ELVSS. Therefore, if leakage current flows inthe first common layer 232, a small amount of light may be generated inthe emission layer 233.

In order to solve this problem, in one embodiment, the first commonlayer 232 is divided into first common layers, each having a sizesmaller than that of the first common layer 232. Dividing the firstcommon layers in this manner is effective to reduce or cut off leakagecurrent. In another embodiment, leakage current may be reduced or cutoff by dividing the first common layer 232 and/or the second commonlayer 234 into first common layers and/or second common layers, eachhaving a size smaller than that of the first common layer 232 and/or thesecond common layer 234.

FIGS. 4A and 4B illustrate a sectional views that correspond to oneembodiment of a method for reducing or cutting off leakage current. Forconvenience, only OLEDs of three adjacent pixels are shown. FIG. 5illustrates a plan view illustrating divided common layers according tothis embodiment.

Referring to FIG. 4A, leakage current may be generated in the firstcommon layer 232 and/or the second common layer 234, so that a pluralityof pixels share the first common layer 232 and/or the second commonlayer 234. For example, leakage current Ileak may be generated along thefirst common layer 232 between the pixels due to parasitic resistance ofthe first common layer 232.

In this case, the second electrode 235 of OLED 235 is coupled to thesecond pixel power source ELVSS. Therefore, if the leakage current Ileakflows in the first common layer 232, the OLED in which the drivingcurrent from pixel circuit 12 is cut off (i.e., the OLED to implement ablack gray scale value by non-emission) may be slightly turned on byleakage current Ileak, so that a small amount of light is generated.This increases black luminance, and therefore results in deteriorationof image quality.

In order to overcome this problem, in one embodiment, the common layerin which leakage current flows (e.g., the first common layer 232) isdivided by being cut at regions between the pixels, as shown in FIG. 4B.Accordingly, it is possible to prevent abnormal emission of the OLEDcaused by leakage current Ileak, thereby improving black luminance.

Although FIG. 4B illustrates that only the first common layer 232 isdivided, in other embodiments only the second common layer 234 may bedivided, or both the first and second common layers 232 and 234 may bedivided, to produce a cut-off effect for the leakage current Ileak.

Also, although FIG. 4B illustrates that the first common layer 232 isdivided for each pixel, the first common layer 232 and/or the secondcommon layer 234 may be practically divided in units of a plurality ofpixels.

For example, as shown in FIG. 5, the first common layer 232 and/or thesecond common layer 234 are/is formed by being patterned in a stripeshape in the horizontal direction on the pixel unit 20. As a result,pixels 10 on consecutive horizontal pixel lines share a single firstcommon layer 232 and/or a single second common layer 234. In oneembodiment, the first common layer 232 and/or second common layer 234may be divided by being cut between the pixels 10 (e.g., an upperportion of the pixel defining layer) in the unit of b vertical pixellines along the vertical direction of the pixel unit 20.

When the first common layer 232 and/or the second common layer 234are/is formed by being patterned in a stripe shape in the verticaldirection on the pixel unit 20, pixels 10 positioned on consecutive bvertical pixel lines share a single first common layer 232 and/or asingle second common layer 234. In this case, the first common layer 232and/or the second common layer 234 may be divided by being cut betweenthe pixels 10 in a unit of horizontal pixel lines in the horizontaldirection of pixel unit 20.

When the first common layer 232 and/or the second common layer 234are/is entirely formed on the pixel unit 20, all pixels 10 share asingle first common layer 232 and/or a single second common layer 234.In this case, the first common layer 232 and/or the second common layer234 may be divided by being cut along the horizontal direction and/orthe vertical direction of the pixel unit 20.

FIG. 5 illustrates the embodiment where the first common layer 232and/or the second common layer 234 are/is formed on the pixel unit 20,by being patterned so that pixels on a plurality of horizontal pixellines and/or a plurality of vertical pixel lines share a single firstcommon layer 232 and/or a single second common layer 234. In o theembodiments, the first common layer 232 and/or second common layer 234may be formed on the pixel unit 20 by being patterned so that pixels onehorizontal or vertical pixel line share a single first common layer 232and/or a single second common layer 234.

In this embodiment, the first common layer 232 and/or the second commonlayer 234 are/is formed by being patterned so that a plurality of pixels10, e.g., k (k is a natural number of 2 or more) pixels 10 share asingle first common layer 232 and/or a single second common layer 234.Then, the first common layer 232 and/or the second common layer 234are/is divided, so that one or more pixels 10 having a number smallerthan that of the k pixels 10 shares a single first common layer 232and/or a single second common layer 234.

For example, in the dividing of the first common layer 232 and/or thesecond common layer 234, one first common layer 232 and/or one secondcommon layer 234 (commonly formed with respect to pixels 10 in the unitof one or more horizontal pixel lines or one or more vertical pixellines) may be divided into at least two first common layers 232 and/orat least two second common layers 234.

The first common layer 232 and/or the second common layer 234 may bedivided into at least two first common layers 234 and/or at least twosecond common layers 234. The divided layers may be disposed withrespect to each of one or more horizontal pixel lines and one or morevertical pixel lines. In this case, the first common layer 232 and/orthe second common layer 234 may be divided into at least two, based oneach of the horizontal and vertical pixel lines on the pixel unit 20.

In the present embodiment, after the process of forming the OLED toinclude the first common layer 232 and/or the second common layer 234 iscompleted (e.g., after the fabricating process for individual panels iscompleted), the first common layer 232 and/or the second common layer234 are/is divided into common layers, each having a size smaller thanthat patterned in the process of forming the first common layer 232and/or the second common layer 234. This may be accomplished, forexample, by applying physical pressure to the panel of the organic lightemitting display.

That is, the first common layer 232 and/or the second common layer 234of the OLED may be formed by being patterned, so that a plurality ofpixels 10 share a single first common layer 232 and/or a single secondcommon layer 234. In this case, the first common layer 232 and/or thesecond common layer 234 may be divided into common layers having asmaller size, which are spaced from one another. This may beaccomplished by applying physical pressure to the first common layer 232and/or the second common layer 234, after the panel fabricating processincluding the process of forming the OLED is completed.

For example, the first common layer 232 and/or the second common layer234 may be divided by applying a force in the vertical direction of aplane on which the substrate is disposed (a plane on which the panel isdisposed), after the panel fabricating process is completed.

Accordingly, leakage current is effectively reduced or cut off throughthe first common layer 232 and/or the second common layer 234.Accordingly, it is possible to prevent an increase of luminance causedby leakage current, thereby improving image quality of the organic lightemitting display.

FIG. 6 illustrates another embodiment of a method of dividing the commonlayer in the organic light emitting display device. For convenience, itis assumed that organic light emitting diodes formed in a panel includeat least one first common layer. However, in a case where the organiclight emitting diodes include only a second common layer, the dividingprocess may divide the second common layer. Also, in a case where theorganic light emitting diodes include both the first and second commonlayers, the second common layer may be simultaneously divided togetherwith the first common layer.

Referring to FIG. 6, a panel 300 of the organic light emitting display,which is fabricated to include at least organic light emitting diode, isplaced on a substrate support 400 having a plurality of grooves 430formed therein. A first common layer in panel 300 is then divided byapplying pressure. This pressure may be transferred to the first commonlayer of the organic light emitting diodes formed in the panel 300.

For example, dividing the first common layer may include placing panel300 on substrate support 400 having a plurality of grooves 430. Thepanel 300 is formed to include one or more organic light emittingdiodes, each including at least a first electrode, a first common layer,an emission layer, and a second electrode. The first common layer ispressed and divided by moving panel 300 and/or substrate support 400 ina second direction intersecting a first direction, while pressing panel30 with a force applied in the first direction perpendicular to thepanel 300.

The first direction may be a direction facing top to bottom, like thedirection of the arrow shown by a dotted line of FIG. 6. The seconddirection intersects the first direction and may be, for example, adirection perpendicular to the first direction, i.e., a directionhorizontal to the panel 300.

The force applied to panel 300 may have intensity such that the firstcommon layer is at least partially cut, by pressing the first commonlayer in the panel 300. In this case, the intensity of the force may beset to be smaller than one which causes a driving failure due tobreakdown of the panel 300, or one which causes damage of anotherdriving electrode, device, or line.

As described in FIG. 3, the first common layer 232 may be formed to becoupled to areas of a plurality of pixels 10R, 10G, and 10B via an upperportion of the pixel defining layer 220. In this case, when a pressingforce is applied to panel 300 on the substrate support 400 havinggrooves 430 formed therein as shown in FIG. 6, the first common layer232 on the pixel defining layer 220 is easily cut. Accordingly, it ispossible to easily divide the first common layer 232 in regions betweenthe pixels 10R, 10G, and 10B. In one embodiment, the force pressing thepanel 300 may be equally applied to the entire surface of the panel 300,in order to prevent a large force from being concentrated on only aportion of the panel 300.

In FIG. 3, the second electrode 235 may be formed of a material havinghigh flexibility, compared with the material of the first common layer232 which may be easily cut or broken. The second electrode 235 may beentirely formed on the pixel unit.

Thus, the material(s) of the first common layer 232 and/or secondelectrode 235 may be selected by taking into consideration of theprocess of dividing the first common layer 232. Also, the process ofdividing the first common layer 232 may be performed by optimizing theforce pressing the panel 300 according to the design conditions of thepanel 300. It is therefore possible to easily divide the first commonlayer 232, while at the same time preventing a driving failure resultingfrom disconnection of the second electrode 235.

The substrate support 400 may be configured to include a plurality ofregions (e.g., a first region 410 and a second region 420), each havinga plurality of grooves 430. The grooves 430 may be formed, for example,at a predetermined interval. For example, each of the first and secondregions 410 and 420 may have a plurality of grooves 430 having the sameinterval and width. The grooves 430 in the first and second regions 410and 420 may be alternately disposed. In this case, the first commonlayer 232 may be more elaborately divided.

When at least one region of the panel 300 is placed in the first region410 on the substrate support 400, the panel 300 may be moved onto thesecond region 420 on the substrate support 400. This may be accomplishedby moving the panel 300 and/or the substrate support 400 in the seconddirection intersecting the first direction, while applying a force inthe first direction perpendicular to the panel 300.

In the aforementioned method embodiment, the first common layer 232 maybe divided by applying physical pressure to the panel 300 after thepanel 300 is fabricated. That is, this embodiment may include dividingfirst common layer 232 while applying physical pressure to first commonlayer 232, in addition to forming the organic light emitting diode onthe substrate 200 as described with reference FIGS. 2 and 3.

Dividing the first common layer 232 may be performed, for example, in astate where a sealing process and a scribing process of dividing thepanel into individual panels 300 are completed. For example, dividingthe first common layer 232 may be performed before, during, or after aprocess of attaching a polarizing plate on panel 300.

For example, the first common layer 232 may be divided by applyingphysical pressure to panel 300 before, during, or after a process ofattaching a polarizing plate on the panel 300. During this process,substrate support 400 having grooves as shown in FIG. 6 may be used asthe substrate support having individual panels 300 mounted thereon. Inthis case, the first common layer 232 can be easily divided withoutadding a separate complicated fabricating process, thereby simplifyingthe fabricating process.

FIG. 7 illustrates another embodiment of a method for dividing thecommon layer in the organic light emitting display device. Referring toFIG. 7, the first common layer in panel 300 may be divided, withoutusing a grooved substrate support 400 as shown in FIG. 6, but rather byusing a roller 500 having grooves 530 formed therein.

More specifically, in this embodiment, the common layer in the organiclight emitting display may be divided by applying a roller 500 withgrooves 530 to panel 300. The panel 300 may include organic lightemitting diodes, each including at least a first electrode, a firstcommon layer, an emission layer, and a second electrode. The firstcommon layer in the panel 300 is divided by moving roller 500 and/orpanel 300 in a second direction intersecting a first direction, whilepressing panel 300 with a force in the first direction perpendicular topanel 300 while rotating the roller 500.

According to one embodiment, a plurality of rollers 510 and 520 may beused. Each of the rollers 510 and 520 may include grooves 530 spaced ata predetermined interval. The rollers 510 and 520 may be rotated, sothat grooves 530 are alternately positioned to cross each other. In thiscase, the first common layer may be more elaborately divided. Grooves530 in roller 500 may be formed in a surface which contacts panel 300.The size and direction of grooves 530 may be variously modified.

FIG. 7 illustrates another embodiment of a method for dividing thecommon layer in the organic light emitting display device. As shown inFIG. 8, the first common layer may be divided using one or more rollers500′ having a plurality of diagonal grooves 530′. The one or morerollers 500′ are disposed on panel 300, and the first common layer maybe divided by rotating rollers 500′ while pressing panel 300 with therollers 500′.

When the first common layer is divided into common layers, each having asize smaller than that patterned in the process of forming the commonlayer as described above, leakage current through the first common layeris effectively reduced or cut off. Accordingly, it is possible toprevent an increase in black luminance, thereby improving image qualityof the organic light emitting display.

By way of summation and review, in an organic light emitting display,driving current is supplied to an organic light emitting diodecorresponding to a data signal. Accordingly, light with a luminancebased on the data signal is emitted to express a corresponding grayscale value. When a black gray scale value is to be implemented, thedata signal has a value which cuts off the driving current to theorganic light emitting diode. As a result, the organic light emittingdiode does not emit light.

However, because of leakage current, the pixel which is to express ablack gray scale value may emit some level of light. That is, anincrease in luminance may occur because the organic light emitting diodeis slightly turned on. Therefore, the black gray scale may not becompletely expressed. As a result, image quality may deteriorate.

In accordance with one or more of the aforementioned embodiments, anorganic light emitting display and fabricating method are provided inwhich multiple pixels share a common layer. This is accomplished bydividing the common layer into common layers of smaller size, which arespaced apart from each other. The common layer may be divided byapplying physical pressure after completion of a panel fabricatingprocess, including one for forming organic light emitting diodes.Accordingly, leakage current is effectively reduced or cut off. Thus, anincrease in luminance caused by the leakage current may be prevented andimage quality of the organic light emitting display may be improved.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of skill in the art as of thefiling of the present application, features, characteristics, and/orelements described in connection with a particular embodiment may beused singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwiseindicated. Accordingly, it will be understood by those of skill in theart that various changes in form and details may be made withoutdeparting from the spirit and scope of the present invention as setforth in the following claims.

What is claimed is:
 1. An organic light emitting display, comprising: aplurality of pixels, each of the pixels including at least one organiclight emitting diode (OLED) which includes: a first electrode and anemission layer in a respective pixel area, a first common layer betweenthe first electrode and emission layer, and a second electrode on theemission layer, a plurality of pixels sharing the first common layer,wherein the first common layer includes at least one opening to divideadjacent ones of the plurality of pixels along a horizontal or verticalpixel line.
 2. The display as claimed in claim 1, wherein the firstcommon layer is disposed to be divided with respect to horizontal andvertical pixel lines.
 3. The display as claimed in claim 1, wherein theOLED includes: a second common layer between the emission layer andsecond electrode, wherein a plurality of pixels share the second commonlayer.
 4. The display as claimed in claim 3, wherein the second commonlayer is divided with respect to a horizontal or vertical pixel line. 5.The display as claimed in claim 3, wherein the second common layer isdivided into smaller second common layers, each smaller second commonlayer having a size smaller than a size of the second common layer. 6.The display as claimed in claim 5, wherein the smaller second commonlayers are spaced apart from one another.
 7. The display as claimed inclaim 1, wherein: the first electrode and emission layer are patternedfor a corresponding one of the pixels, and two or more of the pixelsshare the second electrode.
 8. The display as claimed in claim 1,wherein the first common layer is divided into smaller first commonlayers, each smaller first common layer having a size smaller than asize of the first common layer.
 9. The display as claimed in claim 8,wherein the smaller first common layers are spaced apart from oneanother.
 10. An organic light emitting display, comprising: a pluralityof pixels, each of the pixels including at least one organic lightemitting diode (OLED) which includes: a first electrode and an emissionlayer in a respective pixel area, a first common layer between the firstelectrode and emission layer, a second electrode on the emission layer,and a second common layer between the emission layer and secondelectrode, wherein the plurality of pixels share the first common layer,the plurality of pixels share the second common layer, and the secondcommon layer includes at least one opening to divide adjacent ones ofthe plurality of pixels with respect to a horizontal or vertical pixelline, each portion of the divided second common layer having a sizesmaller than a size of the second common layer.
 11. The display asclaimed in claim 10, wherein the first common layer includes at leastone opening to divide adjacent ones of the plurality of pixels intosmaller first common layers, each of the smaller first common layershaving a size smaller than a size of the first common layer.